The distance between your scrotum and your anus indicates how fertile you are likely to be, say Baylor College of Medicine researchers in the journal PLoS ONE.

"Anogenital distance [the distance between the scrotum and anus] is an important measure for genital development and may be shorter in males with abnormal testicular development and function," explained Dr. Michael Eisenberg, lead author on the study.

For the study, Eisenberg and his research team measured the anogenital distance and penile length of 117 infertile men and 56 fertile men. They found that the infertile men possessed a significantly shorter anogenital distance and penile length when compared with the fertile men.

"There are two main implications of this study - first, this could represent a non-invasive way to test testicular function and reproductive potential in adult men and second, it suggests that gestational exposures and development may impact adult testicular function," concluded Eisenberg.